In the past, pipe lines for transporting steam were provided with expansion joints intermittently along the length so that large compress stresses would not build up in the pipe walls. These prior art joints usually were made in the form of a horseshoe, having an elbow fitted on each end to be coupled within the main pipe line so that the steam travelled through the horseshoe shaped section. The horseshoe section was designed so that its ends could move closer together with moderate force, thus relieving the relatively large stresses which may build up in the main pipe line and prevent the pipe line from buckling. However, these stresses are large enough so that the pipe designer had to take them into consideration when he designed the pipe line.